The Healthy People 2020 goals highlight the need to address social determinants of health to achieve health equity and eliminate health disparities. In the U.S., large racial and socioeconomic disparities in childhood mortality have persisted over time, and are, in fact, widening. Poverty is an overarching risk factor for infant and child mortality, and socioeconomic planning will need to be part of the solution in addition to other health policy. The extant literature is replete with conceptual papers on ecological models and descriptive papers about the extent of disparities, but very few controlled empirical evaluations of the effects of specific laws and policies on disparities. Thus, the proposed intensively longitudinal empirical evaluation of the health effects of policies shaping family economic conditions will substantially advance understanding of how policies can be optimally used to reduce childhood mortality and disparities among low socioeconomic status and racial/ethnic minority children and youth. We propose a 3-phase study, including an intensively longitudinal empirical evaluation of the effects of multiple state-level policies for which there is a strong theoretical basis to expect effects on health disparities. First, we will create a new Family Economic Security Policy Surveillance system with legal/policy data collection and analysis for numerous laws, regulations and specific policies across all 50 states continuously from 1980 to present. Second, we will implement a 35-year 50-state study of geographic and time dispersion to assess the distributions of policies across time and space. Spatial and time analysis will help to delineate solutions for geographic disparities across the U.S. Third, we will evaluate overall effects and differential effects by race/ethnicity and SES of multiple laws and policies on low birth weight, infant mortality and all-cause and cause-specific childhood mortality. We have designed an intensive longitudinal design that takes maximum advantage of over three decades of data across the 50 U.S. states to assess effects of policy changes on childhood mortality and disparities. We will employ an interrupted time-series analysis with matched comparison states propensity-score based synthetic control groups, and nationwide covariate controls to maximize statistical power and strength of causal inference. The scientific results of the proposed study will directly guide law-making to effectively and efficiently improve infant and child outcomes and reduce health and social inequalities and disparities.